Multi-hop Relay Research Articles

Analyses of Relay Nodes Deployment in 4G Wireless Mobile Multihop Relay Networks

In 4G cellular networks: LTE/LTE-Advanced and the mobile WiMAX network, some key impact factors: white Gaussian noise, wireless interference, shadow fading, etc., degrade signal transmission quality and reduce wireless service coverage significantly. The degradations can be improved by deploying more eNBs or BSs, but the expensive eNB/BS extremely increases network cost. The specifications of LTE-Advanced and IEEE 802.16j thus propose a relay-based scheme, namely mobile multihop relay (MMR) networks, to cooperate with the existing cellular network while not obviously increasing the relay station (RS) deployment cost. Various types of RSs: Fixed RS, Nomadic RS and Mobile RS, can be adopted in MMR networks. To efficiently deploy different types of RSs becomes a critical issue. Thus, this paper first analyzes the impact factors: transmission quality, deployment price, service coverage and RS overlap index, and then models the cost-effective issue of the RS deployment as an optimization problem. The paper proposes an adaptive cost-based RS deployment (ACRD) approach to form a cost function in terms of all impact factors, and then solves the optimization problem by determining the RS deployment with the least network cost as the solution. Numerical results demonstrate that ACRD outperforms the compared approaches in network cost, transmission quality, RS deployment price, service coverage, and RS overlap index. Additionally, ACRD deploys more RSs on the areas with high-density populations and thus increases transmission quality and guarantees the quality of service (QoS). Finally, the worst case running time of ACRD is analyzed, which requires $$ T(n) = O(I \cdot P) $$T(n)=O(I·P).

Secure Authentication and Key Management Protocols for Mobile Multihop WiMAX Networks

Mobile Multihop Relay (MMR) network is one of the emerging technologies, especially LTE-Advanced, WiMAX and the Smart grid communications. Ensuring security is one of the most imperative and challenging issues in MMR networks. Privacy Key Management (PKM) protocol is proposed to ensure the security measures in MMR networks. However, the protocol still faces several security threats, specifically Denial of Service (DoS), replay attacks, Man in the Middle (MitM) attacks and the interleaving attacks, which is termed as Medium Access Control (MAC) layer attacks. This paper proposed a modified version PKM protocol for both unilateral and mutual authentication, which is termed as Self-organized Efficient Authentication and Key Management Scheme (SEAKS) authentication protocol. This protocol ensures secure end-to-end data transmission using distributed hop-by-hop authentication and localized key management schemes with a very simple and efficient way.

Opportunistic Routing Algorithm for Relay Node Selection in Wireless Sensor Networks

Energy savings optimization becomes one of the major concerns in the wireless sensor network (WSN) routing protocol design, due to the fact that most sensor nodes are equipped with the limited nonrechargeable battery power. In this paper, we focus on minimizing energy consumption and maximizing network lifetime for data relay in one-dimensional (1-D) queue network. Following the principle of opportunistic routing theory, multihop relay decision to optimize the network energy efficiency is made based on the differences among sensor nodes, in terms of both their distance to sink and the residual energy of each other. Specifically, an Energy Saving via Opportunistic Routing (ENS_OR) algorithm is designed to ensure minimum power cost during data relay and protect the nodes with relatively low residual energy. Extensive simulations and real testbed results show that the proposed solution ENS_OR can significantly improve the network performance on energy saving and wireless connectivity in comparison with other existing WSN routing schemes.

A cluster-based relay station deployment scheme for multi-hop relay networks

Multi-hop relay networks have been widely considered as a promising solution to extend the coverage area and to reduce the deployment cost by deploying the relay stations (RSs) in mobile communication systems. Suitable deployment for the RSs is one of the most important features of the demand nodes (DNs) to obtain a high data transmission rate in such systems. Considering a tradeoff among the network throughput, the deployment budget, and the overall coverage of the systems, efficient RS deployment schemes and corresponding algorithms must be developed and designed. A novel cluster-based RS deployment scheme is proposed in this paper to select the appropriate deployment locations for the relay stations from the candidate positions. To make an ideal cluster distribution, the distances between the DNs are calculated when deploying the RSs. We take into account the traffic demands and adopt a uniform cluster concept to reduce the data transmission distances of the DNs. On the basis of the different candidate positions, the proposed scheme makes an adaptive decision for selecting the deployment sites of the RSs. A better network throughput and coverage ratio can be obtained by balancing the network load among the clusters. Simulation results show that the proposed scheme outperforms the previously known schemes in terms of the network throughput and the coverage ratio. Additionally, a suitable deployment budget can be implemented in multi-hop relay networks.

MASK-BAN: Movement-Aided Authenticated Secret Key Extraction Utilizing Channel Characteristics in Body Area Networks

Recently, most wireless network security schemes merely based on physical layer characteristics tackle the two fundamental issues-device authentication and secret key extraction separately. It remains an open problem to simultaneously achieve device authentication and fast secret key extraction merely using wireless physical layer characteristics, without the help of advanced hardware or out-of-band channel. In this paper, we answer this open problem in the setting of wireless body area networks (BANs). We propose MASK-BAN, a lightweight fast authenticated secret key extraction scheme for intra-BAN communication. Our scheme neither introduces advanced hardware nor relies on out-of-band channels. To perform device authentication and fast secret key extraction at the same time, we exploit the heterogeneous channel characteristics among the collection of on-body channels during body motion. On one hand, MASK-BAN achieves authentication through multihop stable channels, which greatly reduces the false positive rate as compared to existing work. On the other hand, based on dynamic channels, key extraction between two on-body devices with multihop relay nodes is modeled as a max-flow problem, and a novel collaborative secret key generation algorithm is introduced to maximize the key generation rate. Extensive real-world experiments on low-end commercial-off-the-shelf sensor devices validate MASK-BAN's great authentication capability and high-secret key generation rate.

An Efficient Base Station and Relay Station Placement Scheme for Multi-hop Relay Networks

A multi-hop relay network has been widely considered as a promising solution to extend the coverage area and to reduce the deployment cost by the placement of relay stations in mobile communication systems. Suitable placement for the base stations and relay stations is one of the most important features of the demand nodes to obtain a high data transmission rate in such environments. In order to obtain a favorable network throughput, deployment budget, and overall coverage of the systems, efficient base station and relay station placement schemes and corresponding algorithms must be developed. In this paper, an efficient placement scheme is proposed to select the appropriate placement locations for the base stations and the relay stations from the candidate positions. We account for the coverage ratio and the traffic ratio between the data transmission rate and the traffic demand. On the basis of the different candidate positions, the proposed scheme makes an adaptive decision for selecting the placement sites of the base stations and relay stations by employing a fuzzy inference mechanism. A better network throughput and coverage ratio can be obtained by balancing the network load. Simulation results demonstrate the superior performance of our proposed scheme and its ability to strike the appropriate performance in the network throughput and the overall coverage of the systems. Additionally, a suitable deployment budget can be implemented in multi-hop relay networks.

A Unified Approach to Performance Analysis of Multihop Relay Fading Channels Using Generalized Gamma Model

AbstractIn this paper analysis of various fading statistics of generic fading distribution, termed as

Techniques to Enhance the Quality of Service of Multi Hop Relay Networks

Broadband internet access through the user equipment has become the hot research topic. The shadowing and multipath issues restrict the high performance nature of 4G cells. In Multi hop Relay (MHR) networks, Relay Stations (RS) are introduced to improve coverage and capacity of the system. There exist some issues like path selection and RSs deployment, which severely affects the Quality of Service (QoS) of the system. In this paper, to improve the QoS of MHR networks, Load Aware Routing Metric (LARM) based path selection and a low complex Burst Profile (BP) based RS deployment schemes are discussed.

Quality of Service Aware Multi-Hop Relay Networks for Green Radio Communication

In recent years, issues on greenhouse pollution and power consumption related to the operation of information communication technology (ICT) devices have triggered a huge amount of research work towards green radio communication. Many of the power efficient solutions will introduce cost performance trade-offs. The energy efficient solution which also takes care of the quality requests of the mobile customer is really required for the 5G basedgreenradiocommunication.ItisidentifiedthatenhancednodeBs(eNB) are power inefficient and not suited for many deployment scenarios. Multihop relay (MHR) network is the suitable alternate for eNB especially in the coverage holes and cell edges. But MHR network suffers by various quality issueslikesiteplanningandpathselection. Manyofthesiteplanningandpath selection schemes will fail under network imbalance conditions. In this work, we have proposed a hybrid throughput oriented (TO) ‐ load aware spectral efficient routing (LASER) scheme which offers high performance even under network load imbalance conditions. The simulation results proved that the proposed scheme is more suited for future green radio communication.

Cross-Layer Design and Performance Analysis of Tactical Radio Networks

In this paper, we investigate the performance of tactical radio networks, particularly for communication scenarios where multihop relaying along with spatial reuse techniques are applied. The tactical scenarios of concern have a diverse range of reliability and/or delay requirements. We first employ cross-layer protocol architecture with integrated time-division-multiple-access-based fast packet forwarding and automatic-repeat-request-based multihop error control to support tactical applications with a diverse range of reliability and/or delay requirements. Then, we develop analytical models to study the link-level and network-wide behaviors of the tactical radio networks. The developed models capture the effects of end-to-end channel memory due to multihop relays, interference due to spatial reuse, uneven interslot delays due to fast packet forwarding, and jamming attack in hostile network environment. It is shown that the protocol architecture with proposed fast packet forwarding and multihop error control mechanisms can significantly improve communication performance and support delay-sensitive applications. In addition, it is demonstrated that cross-layer adaptivity, where different network environments require different logical topologies and radio modes, is needed to achieve best performance tradeoffs among throughput, efficiency, delivery ratio, and transport capacity.

Study on a resource allocation scheme in multi-hop MIMO-OFDM systems over lognormal-rayleigh compound channels

For new generation wireless communication networks,this paper studies the optimization of the capacity and end-to-end throughput of the MIMO-OFDM based multi-hop relay systems. A water-filling power allocation method is proposed to improve the channel capacity and the throughput of the MIMO-OFDM system based multi-hop relay system in the Lognormal-Rayleigh shadowing compound channels. Simulations on the capacity and throughput show that the water-filling algorithm can improve the system throughput effectively in the MIMO-OFDM multi-hop relay system.

Multi-User Multi-Hop Relay Networks: Transmission Schemes and Degrees of Freedom

We study the achievable sum degrees of freedom (DoF) in wireless single-antenna multi-user multi-hop relay networks. In most existing works targeting this problem, it is assumed that relays operate in perfect full-duplex fashion and can also shield their receptions from the transmissions of other relays in the same and rear layers. In practice, such ideal assumptions are normally hard to realize. And a naive adoption of half-duplex operation in relays may result in significantly inefficient use of available radio resources. We propose spectrally-efficient transmission schemes to address this issue. A lower-bound to the networks' available DoF (i.e., optimally achievable sum DoF) hence can be attained. Our results indicate that besides providing information delivery paths, relays can also bring DoF gain over single-hop networks, even when relay interference issues are taken into consideration. This lower-bound would approach the upper-bound of the available DoF, if each relay layer deploys more nodes. When the number of relays in every layer is infinitely large, the exact available DoF is identified, which shows that handling interference issues through distributed signal processing and half-duplex operation across multiple layers of terminals may not negatively affect DoF performance, compared with ideal full-duplex and multi-antenna networks.

Outage Performance of MIMO Multihop Relay Network with MRT/RAS Scheme

Outage Performance of MIMO Multihop Relay Network with MRT/RAS Scheme

Lightweight Message Authentication Protocol for Mobile Multihop Relay Networks

This paper proposes a lightweight self-organized efficient authentication and key management scheme (SEAKS) to countermeasure the MAC layer attacks such as denial of service (DoS), replay attack, man-in-the-middle attack and the interleaving attacks in mobile multihop relay (MMR) networks. SEAKS has been developed based on privacy key management (PKM) protocol for both unilateral authentication defined as SEAKS-PKMv1 and mutual authentication as SEAKS-PKMv2. In SEAKS, the non-transparent relays (N-RS) perform authentication and establish the authorization key (AK) using our proposed public key cryptosystem based on hash authentication code scheme. The subsequent N-RS can be authenticated with less overhead thus enhancing the scalability of the system. The performance of SEAKS-PKMv1 and SEAKS-PKMv2 protocol has been evaluated using BAN LOGIC to verify the integrity of the participating N-RSs and SSs. Simulation study shows that SEAKS exhibits higher packet delivery ratio by 22%, lesser packet overhead by 12%, and less processing time by 14% as compared to the official draft scheme (OD-2009) for MMR WiMAX networks. SEAKS can be applied to any multihop networks with minimum authentication overhead.

Performance analysis of a multihop relay network using distributed Alamouti code

In this paper, we apply the classical Alamouti coding technique in a distributed and cascaded fashion to multihop relay networks where relays perform the decode-and-forward (DF) protocol at each relay stage. The considered system consists of two antennas at the source, two single-antenna relays at each relay stage and one antenna at the destination. The source transmits at each coding step two symbols according to the Alamouti code, to the first relay stage where each relay decodes the two symbols independently. The two relays of each relay stage behave like the two antennas of the source and transmit the two estimated symbols to the next relay stage until the destination using distributed Alamouti code. We obtain a closed form expression for the outage probability of the N-hop relay network and derive a tight analytical upper bound for the bit error probability at the destination, by considering the two-hop case firstly and then generalizing for the N-hop networks. We also show that DF protocol provides better bit error performance compared to the amplify-and-forward protocol previously considered in the literature for N-hop relay networks.

Reliable Cooperative Communications Based on Random Network Coding in Multi-Hop Relay WSNs

Reliability is an important issue when designing wireless sensor networks (WSNs), since the WSNs need to work for a long time without manual interventions. Many techniques, such as multiple input multiple output systems and low density parity check codes, have been devised to improve the reliability of computer networks and wireless networks. However, these techniques are too complicated to apply in the WSNs due to the extremely limited resources of the wireless sensor nodes. Hence, it is a hot research topic to design a reliable scheme with low complexity in the WSNs. In recent years, there are a few schemes proposed to improve transmission reliability in the WSNs, such as multipath routing and cooperative transmission. In this paper, a network coding-based cooperative communications scheme (NCCC) is proposed. Combining the advantages of both cooperative communications and network coding, the NCCC can improve the packet loss-resistant capability through network coding and the communications fail-resistant capability through cooperative communications. In the NCCC, coding vectors in network coding procedure are chosen from a finite field randomly, which makes the NCCC easy to be implemented in the resource-limited sensor nodes. Theoretical analyses and experimental results show that the NCCC can achieve a good reliability performance at the cost of neglectable delay.

On the Optimal Link Adaptation in Linear Relay Networks With Incremental Redundancy HARQ

In this letter, we investigate a joint power and rate optimization for a multihop relay network with incremental redundancy hybrid ARQ (HARQ-IR), where multiple relays are serially connected from a source to a destination. The optimization problem is to adjust both transmission rate and power of each node in order to maximize long-term average transmission rate (LATR) for given sum-power and delay constraints, which is unfortunately not mathematically tractable. Hence, we propose a sub-optimal algorithm to improve the LATR, which is computationally efficient and has comparable performance with the exhaustive search algorithm. Simulation results show that the proposed algorithm outperforms the conventional algorithms, including the HARQ-IR scheme with fixed power and rate and the Chase-combining HARQ scheme of which both power and rate are optimized for the same network.

VLC 기반 멀티 홉 멀티미디어 데이터 전송 네트워크 시스템

In this paper, we propose VLC(visible light communication) based multi-hop multimedia data transmission system. The main contributions and features of the proposed system are as follows. First, the contribution of this research is to develope the LED communication based multi-hop transmission network system which can transmit multimedia data(audio data, video data) with long distance. Second, the developed system has the following features: In transmitter, audio data and video data are transmitted via multi-hops using two channels. The relay in audio channel receives digital audio signal by using photo diode and then transmits the signal to receiver after error checking and amplifying. The receiver receives the encoded audio data via photo diode and then converts to analog audio signal by using decoding and amplifying. The relay in video channel receives video signal by using photo diode and then amplify the video signal using OP-AMP and then transmits the signal to receiver. The receiver amplifies the received signal from photo diode and then sends it to the monitor. The performance evaluation of the proposed system is conducted in the laboratory with fluorescent light source. The results of the performance evaluation confirm that the system can provide high quality multimedia data transmission from transmiter to receiver via multi-hop relays in a long distance while we can see there are differences in the transmitted multimedia(audio and video) quality according to the used LED colors.

Energy-aware routing for delay-sensitive underwater wireless sensor networks

The energy reduction is a challenging problem in the applications of underwater wireless sensor networks (UWSNs). The embedded battery is difficult to be replaced and it has an upper bound on its lifetime. Multihop relay is a popular method to reduce energy consumption in data transmission. The energy minimum path from source to destination in the sensor networks can be obtained through the shortest path algorithm. However, because of the node mobility, the global path planning approach is not suitable for the routing in UWSNs. It calls for an energy-efficient routing protocol for the high dynamic UWSNs. In this paper, we propose the modified energy weight routing (MEWR) protocol to deal with the energy-efficient routing of delaysensitive UWSNs. MEWR is a low flooding routing protocol. It can tolerate the node mobility in UWSNs and achieve a low end-to-end packet delay. MEWR can provide lower energy consumption than the existing low delay routing protocols through the dynamic sending power adjustment. The simulation results demonstrate the effectiveness of MEWR.

REDUCING TRANSMITTED POWER OF MOVING RELAY NODE IN LONG-TERM EVOLUTION-ADVANCED CELLULAR NETWORKS

Wireless multi-hop relay networks have become very significant technologies in mobile communications. These networks ensure data rate transfer and covera ge extension with a low cost. In this study two typ es of relay are studied; Fixed Relay Node (FRN) and Moving Relay Node (MRN). Where system analyses for uplink and downlink transmission are derived in thi s study. Moreover the optimal relay location of FRN was proposed to provide a maximum achievable rate at user in cell edge region. Finally, a new algorith m was suggested to balance and control on the transmi tted power of MRN over cell size to provide the required SNR and throughput at the users inside veh icle with reducing the consumption transmitted rela y power. Numerical results indicate an enhancement in received signal strength for users at the cell edg e from (-90 to -65) dBm and 40% increment from all cell size after de ploying FRN at proposed locations. As well as, the results revealed that there is saving nearl y 75% from transmitted power in MRN after using proposed algorithm. ATDI simulator was used to verify the nu merical results, which deals with real digital cartographic and standard formats for terrain.